Templation in the formation of carceplexes

The formation of carceplexes and hemicarceplexes involves an assembly process whereby a molecular template is entrapped between two bowl-shaped molecules. The process can be highly selective such that a million-fold range in template recognition has been realized. The relative template abilities, or template ratios, for 34 molecules in forming carceplex a guest is described. Species with one, two, and three bridges linking the two "bowls" are reported and were used to delineate the guest-determining step of the reaction. The effect of base and solvent on the reaction are also described, and a discussion of the reaction mechanism is presented.